US3953739A - Method and apparatus for the continuous monitoring and control of cell size in a foam structure - Google Patents

Method and apparatus for the continuous monitoring and control of cell size in a foam structure Download PDF

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Publication number
US3953739A
US3953739A US05/510,666 US51066674A US3953739A US 3953739 A US3953739 A US 3953739A US 51066674 A US51066674 A US 51066674A US 3953739 A US3953739 A US 3953739A
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United States
Prior art keywords
foam
cell size
color
light
photocell
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Expired - Lifetime
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US05/510,666
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English (en)
Inventor
Edward A. Colombo
James Tarng Tsai
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Mobil Oil AS
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Mobil Oil AS
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Publication date
Application filed by Mobil Oil AS filed Critical Mobil Oil AS
Priority to US05/510,666 priority Critical patent/US3953739A/en
Priority to GB38629/75A priority patent/GB1522644A/en
Priority to BE160454A priority patent/BE833910A/xx
Priority to ES441291A priority patent/ES441291A1/es
Priority to DE19752543292 priority patent/DE2543292A1/de
Priority to JP50116544A priority patent/JPS5161885A/ja
Priority to CA236,656A priority patent/CA1065567A/en
Priority to IT27766/75A priority patent/IT1042966B/it
Priority to NL7511471A priority patent/NL7511471A/xx
Priority to FR7529945A priority patent/FR2285983A1/fr
Application granted granted Critical
Publication of US3953739A publication Critical patent/US3953739A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/36—Feeding the material to be shaped
    • B29C44/46—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length
    • B29C44/50—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length using pressure difference, e.g. by extrusion or by spraying
    • B29C44/507—Feeding the material to be shaped into an open space or onto moving surfaces, i.e. to make articles of indefinite length using pressure difference, e.g. by extrusion or by spraying extruding the compound through an annular die

Definitions

  • the present invention relates to a method and apparatus which employ reflected light to continuously measure the individual cell size of cells contained in an extruded plastic foam product such as polystyrene foam.
  • an extruded plastic foam product such as polystyrene foam.
  • prompt processing and/or material feed e.g., blowing agent, nucleating agent, etc.
  • cell size is the structural parameter which can be modified most readily and, furthermore, has a pronounced effect on the foam's properties. These properties include compressive strength, tensile strength, elongation at break, tear strength and thermal insulating values. Cell size can be varied by orders of magnitude in a full scale production process by manipulating the necessary process parameters, nucleating agent, melt temperature, and so forth. The quantification of cell size is under normal circumstances tedious and time consuming. Normally a thin section of foam is prepared using a suitable cutting device, microtome or its equivalent.
  • the present invention provides a continuous in-line method and apparatus for determining the cell size of polymeric foams as they are extruded. Further, the present invention provides an arrangement whereby in the event the monitored cell size of the foam is not within product specifications, automatic adjustments may be made to extrusion line conditions and/or to the extrusion feed materials to bring the cell size of the foam material within the desired specifications.
  • the present invention relates to an apparatus and method for determining the average individual cell size of a plastic foam structure which comprises illuminating the surface of said foam, receiving and collecting at least a portion of the light which is diffused from said foam with a detector photocell, electrically measuring the amount of light energy received by said photocell whereby said light energy measurement is directly converted to said cell size.
  • FIG. 1 is a schematic diagram of a rectangular color solid.
  • FIG. 2 is a plot of the International Committee on Illumination [ICI] of the primary stimuli of specified proportions of light of certain wave lengths.
  • FIG. 3 is a schematic circuit diagram of a colorimeter which may be employed in the practice of the present invention.
  • FIG. 4 is a simplified schematic circuit diagram showing the circuit of FIG. 3 with the selector switch in the L position.
  • FIG. 5 is a plot of individual foam cell size radius versus L values.
  • polystyrene foam material which has a relatively small cell size, e.g., on the order of about 0.25 to 0.75 mil cell size radius appears to have a relatively lighter color
  • polystyrene foam which is constituted by individual cells which have a relatively larger cell size, e.g., on the order of from about 1 to 10 mils cell size radius.
  • the mixture is fed to a standard rotating screw type extruder, wherein it is thoroughly mixed and melted as it is advanced towards the exit end of the extruder.
  • a blowing agent such as pentane or isopentane is injected into the extruder downstream of the feed hopper.
  • the pentane blowing agent is thorougly admixed with the melted polystyrene and nucleating agent and this mixture is eventually extruded from the extrusion system through a die, either in the form of a flat foam sheet or a tubular structure which is subsequently cooled, and the polystyrene foam sheeting recovered.
  • the prime control means for adjusting foam cell size is usually by control of the concentration of nucleating agents in the extrusion system. This concentration however, during continuous extrusion processes, may vary somewhat due to the vagaries of the system such as erratic feed at the nucleant feed hopper, incomplete or non-uniform mixture of the nucleants with the resin, and other undesirable conditions. Applicants have now found that irregularities in the size of the cell in the extruded foam sheet may be continuously monitored and quickly discovered and corrected by continuous measurement of the color, i.e., color shading differences of the foam sheet.
  • color may be specified by assigning numerical values to the quantity of each wavelength of light in that color.
  • these numerical values are cumbersome and not readily useful because values representing the humanly observed properties of colors are obtainable from them only by extensive calculation.
  • ICI International Committee on Illumination
  • FIG. 2 of the drawings is a plot of the ICI primary stimuli.
  • Each of these primary stimuli is an assembly of specified proportions of light of certain wavelengths and represents the maximum of a family of curves.
  • the X curve represents an essentially red stimulus, the Y curve an essentially green stimulus, and the Z curve an essentially blue stimulus.
  • Any color can be represented by a curve in each family. Ordinates of the maximums of the curve in each family are the tristimulus coefficients of the color.
  • the Y curve was selected by ICI so the plot of the proportion versus wavelength corresponds to the light sensitivity curve of the normal human eye; the ordinate of the Y curve of the color, corrected for the intensity of the illuminating sourve, identifies the intensity of the color.
  • the hue and the saturation of the color can be readily calculated from its tristimulus coefficients by using the chromaticity diagram described by Margenau, Watson and Montgomery, Physics Principles and Applications 673-677 (2nd Edition, McGraw-Hill Book Co., New York, 1953).
  • the vertical axis represents the lightness which varies from black to white through the various degrees of grayness.
  • the hue is represented by the direction from the axis, the various directions corresponding to red, yellow, green, blue, purple or intermediate colors; and the saturation is represented by the length of the radius extending from the gray or lightness axis to the periphery representing the strongest colors.
  • FIG. 1 illustrates a commonly used arrangement for depicting colors in terms of three values, generally corresponding to those of the conventional color solid, but conforming to a three dimensional Cartesian coordinate system. An arbitrary scale of values is assigned to each coordinate as shown.
  • the system of color classification and designation employed in the commercially available color difference meter used in the following examples is based upon the rectangular solid color shown in FIG. 1.
  • the L scale ranges from 0-100 (black to pure white). This scale is related to the reflectance of a sample and is used, for purposes of the following specific embodiments of the present invention, to correlate cell size and scattered light.
  • FIG. 3 illustrates a schematic circuit diagram showing the principle of operation.
  • L k 1 ⁇ Y
  • a k 2 (X-Y) ⁇ Y
  • b k 3 (Y-Z) ⁇ Y, in which a indicates RED when plus and GREEN when minus, and b indicates YELLOW when plus and BLUE when minus.
  • k 1 , k 2 and k 3 are constants which are controlled by the various resistance ratios in the circuit.
  • the instrument computes the difference in the L, a or b (X, Y or Z) values of the standard and sample.
  • the equation is sample - standard.
  • the optical head In the optical head, light is received by the phototubes through optical filters which control the spectral character of the light.
  • the currents generated by the phototubes are protional tristimulus functions X, Y and Z.
  • the flow of this current into operational amplifiers, in the optical head generates voltage signals proportional to the tristimulus functions.
  • These signals are routed to the difference amplifier board in the measurement unit where the photodetector dark currents are corrected for, and the k 2 (X-Y) and k 3 (Y-Z) computations are made.
  • Five signals from this board (X, Y, Z, k 2 (X-Y) and k 3 (Y-Z)) are routed to the selector switches.
  • the Y signal is also routed to the square root board where ⁇ Y is computed and routed to the selector switches.
  • the selector switches enable the operator to select the function to displayed, i.e., L, a or b.
  • the specimen 2, which is being measured is illuminated with light from a suitable source 76, at an angle of 45° in the case of a reflecting specimen (as contrasted with a light transmitting specimen), through a suitable diffusing plate 15.
  • a practical exposure unit uses a low voltage halogen cycle lamp calibrated with a lamp voltage of approximately 9.75 volts to produce a known color temperature.
  • the lamp in combination with lenses and mirrors produce 2 beams so as to strike the surface of the specimen from opposite directions at angles of 45°, as shown in FIG. 3.
  • Photocells 3, 4 and 5 Light reflected from the specimen in perpendicular and near perpendicular directions is measured by photocells 3, 4 and 5, giving respectively the Y, X and Z signals by virtue of tristimulus light filters 7, 8 and 9 placed between the photocells and the light reaching them.
  • the degree to which photocell 3 is stimulated by the reflected light from the specimen is used as an indication of the lightness factor L; similarly cell 4 is used to provide (in combination with cell 3) a signal which is a function of the RED-GREEN factor a; and cell 5 is used in the same manner for the YELLOW-BLUE factor b, referring to the schematic diagram of FIG. 1.
  • the circuits used are energized by a constant voltage D-C. supply 11, to which is connected a difference potentionmeter 13 for zero setting of the instrument.
  • the meter is fed signals form two signal lines 14 and 16 through a dual-triode 17, the grids of which are connected to the respective signal lines, while their plates are connected to their respective meter inputs, whereby the meter is initially adjusted by potentiometer 13 to zero scale position and thereafter measures the differences between the D.C. voltage levels of the signals supplied to it by lines 14 and 16.
  • the ungrounded side of line 11 is also connected through a fixed resistor 17 and an adjustable resistor or potentiometer 18 to the slider of a reference potentiometer 19.
  • One end of potentiometer 19 is connected through line 21 to point 22 and thence through a fixed resistor 23 to ground.
  • the other end of potentiometer 19 is connected through the L setting of selector switch 24 to line 26 and thence through resistor 27 to a bridge arrangement 28 consisting of a potentiometer 29 and fixed resistor 31 connected in parallel as shown.
  • the lower common end of bridge 28 is connected through resistor 32 to lead 21.
  • a gas-tube regulator 33 is connected between point 22 and line 11 to aid in regulating and in maintaining essentially constant current through resistance 23 in the face of adjustments of potentiometer 18. This voltage regulation is necessary in order to hold phototube voltages and grid voltages in the tube 17 nearly constant.
  • the slider 30 of potentiometer 29 is connected through selector switch 34, in the L position shown in FIG. 3, to a load resistor 36 connected to the anode of photocell 3.
  • Line 14 of the difference meter is connected to the common point of resistors 29 and 32 via line 37 and switch 38 while line 16 of the meter is connected via switch 39 to point Y, which is at the anode potential of tube 3.
  • the elements above described are essentially all of the circuit elements involved in the L setting of switch 24, that is, the setting used in obtaining the value of L, which, as was indicated above, is one of the three values needed to identify a color. These elements are separated out from the rest of the circuit and redrawn in FIG. 4 in order to show more clearly the circuits used in obtaining the L value.
  • the same reference characters are employed as in FIG. 3 to facilitate comparison of the two circuit drawings.
  • this circuit is arranged as a substantially constant current circuit, so far as the effect of variation of the sliders of reference potentiometer 19 and Y balance potentiometer 29 are concerned.
  • These two sliders are ganged; that is, they are fixed to move together so that they are both always at the same relative position on their respective resistance windings.
  • the resistors 31 and 29 due to the high series resistance of element 17 and the low resistance bridging elements 27 and 32 as well as the parallel bridging paths presented by the resistors 31 and 29, it will be apparent that as sliders 20 and 30 move along their respective resistance elements, the total current flow through slider 20 will remain substantially constant, since the net series resistance variation introduced by movement of the sliders in the bridging circuit shown is negligibly small.
  • the circuit thus functions, in effect, as a constant current bridge, and for all practical purposes, the current through slider 20 may be considered as a constant current.
  • the bridge is adjusted by varying the position of ganged sliders 20 and 30 until the difference meter reads zero, that is, the voltage drop across load resistor 36 of photocell 3 is balanced out.
  • the scale setting is noted which corresponds to the distance from point zero of potentiometer 29 to the slider; this distance gives the value of Y 1/2 , which corresponds to the desired reading for the value L.
  • Similar circuits are described in U.S. Pat. No. 3,003,388, the disclosure of which is incorporated herein by reference.
  • the colorimeter can be calibrated to produce tristimulus coefficients directly or it can be used to measure color differences between a standard and a material.
  • standardization of the colorimeter is accomplished by obtaining tristimulus coefficients of the color standard.
  • a standard having color characteristics as close as possible to the material is used.
  • standards preferably have the color characteristics of the foam product under examination. Once coefficients of a color standard have been recorded, the colorimeter may be easily recalibrated to that standard.
  • the value given by the L scale of the colorimeter i.e., the scale which registers a value corresponding to a samples' lightness or darkness
  • a black background is employed for mounting the polystyrene foam specimen being examined.
  • Polystyrene resin pellets were admixed with a nucleating agent mixture comprising sodium bicarbonate and anhydrous citric acid.
  • the nucleating agents constituted 0.58% by weight based upon the total weight of the polystyrene feed charge.
  • the acid to bicarbonate ratio was 1:0.76.
  • the portion of the extruder barrel surrounding the feed zone of the extruder was maintained at a temperature of about 220° F.
  • the extruder barrel was maintained at a temperature of from about 400° to 450° F.
  • a liquid pentane blowing agent was injected through the extruder barrel, about 5% by weight of pentane based upon the total weight of resin and nucleating agent, and into the polystyrene composition at a point beyond the feed section where the polystyrene was in a molten condition.
  • the molten mass was than passed through the extruder mixing zone and finally through the cooling section of the extrusion system before being extruded through an annular die orifice, affixed to the terminal end of the extruder.
  • Example 1 The procedure of Example 1 was employed to produce additional samples in Examples 2 through 13 inclusive, the concentration of nucleating agents being varied, as shown in the following Table I.
  • the data obtained from the preceeding examples was plotted to obtain a master curve, correlating the L reading from the colorimeter with the cell radius of individual cells in the foam samples.
  • a master curve correlating the L reading from the colorimeter with the cell radius of individual cells in the foam samples.
  • the colorimeter was easily mounted above the continuous running web of polystyrene foam and the L value of the foam was continuously registered on the colorimeter digital read-out. This measurement may be continuously recorded on an advancing recording chart. Whenever it appeared that the L value was either too high or too low with respect to the particular cell size desired, a simple adjustment was made, automatically (e.g., by computer control) if desired, to either increase the concentration of the nucleating agent being admixed with the resin prior to introduction of the mixture into the extrusion system. As hereinbefore noted, it is also possible to vary other process parameters to obtain variation in cell size such as, for example, density, blowing agent concentration, melt temperature and others.

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  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Optical Measuring Cells (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Molding Of Porous Articles (AREA)
  • Spectrometry And Color Measurement (AREA)
US05/510,666 1974-09-30 1974-09-30 Method and apparatus for the continuous monitoring and control of cell size in a foam structure Expired - Lifetime US3953739A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US05/510,666 US3953739A (en) 1974-09-30 1974-09-30 Method and apparatus for the continuous monitoring and control of cell size in a foam structure
GB38629/75A GB1522644A (en) 1974-09-30 1975-09-19 Control of foam cell size by measuring reflected light
ES441291A ES441291A1 (es) 1974-09-30 1975-09-26 Un metodo para determinar el tamano medio de las celdas in- dividuales de una estructura de esponja de resina.
BE160454A BE833910A (fr) 1974-09-30 1975-09-26 Procede et appareil de mesure continue de la grosseur des alveoles d'un produit en mousse
DE19752543292 DE2543292A1 (de) 1974-09-30 1975-09-27 Verfahren zur herstellung eines extrudierten geschaeumten kunststoffkoerpers
JP50116544A JPS5161885A (cs) 1974-09-30 1975-09-29
CA236,656A CA1065567A (en) 1974-09-30 1975-09-29 Control of foam cell size by measuring reflected light
IT27766/75A IT1042966B (it) 1974-09-30 1975-09-29 Metodo ed apparato per la rilevazione continua ed il controllo delle dimensioni delle celle in una struttura espansa
NL7511471A NL7511471A (nl) 1974-09-30 1975-09-29 Werkwijze voor het vormen van een geextrudeerd kunststofschuim.
FR7529945A FR2285983A1 (fr) 1974-09-30 1975-09-30 Procede et appareil de mesure continue de la grosseur des alveoles d'un produit en mousse

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US05/510,666 US3953739A (en) 1974-09-30 1974-09-30 Method and apparatus for the continuous monitoring and control of cell size in a foam structure

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US (1) US3953739A (cs)
JP (1) JPS5161885A (cs)
BE (1) BE833910A (cs)
CA (1) CA1065567A (cs)
DE (1) DE2543292A1 (cs)
ES (1) ES441291A1 (cs)
FR (1) FR2285983A1 (cs)
GB (1) GB1522644A (cs)
IT (1) IT1042966B (cs)
NL (1) NL7511471A (cs)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4374322A (en) * 1979-04-27 1983-02-15 W. C. Heraeus Gmbh Apparatus for controlling the absorption of one or more color components in a dyeing fluid
US4412961A (en) * 1981-12-23 1983-11-01 Mobil Oil Corporation Method and apparatus for measurement and control of cell size in a foam structure
US4699516A (en) * 1984-10-29 1987-10-13 The Dow Chemical Company Apparatus and methods for determining cell size
DE3813662A1 (de) * 1987-04-23 1988-11-17 Hajime Industries Oberflaechenpruefgeraet
US5248459A (en) * 1989-11-25 1993-09-28 Kanegafuchi Chemical Industry Co., Ltd. Method of manufacturing molded resin foam and apparatus therefor
US5509795A (en) * 1993-11-23 1996-04-23 Schuller International, Inc. Apparatus for continuously foaming a polyimide powder
US5912729A (en) * 1996-06-17 1999-06-15 Basf Corporation Measurement of plastic foam cell size using a visualization technique
FR3015021A1 (fr) * 2013-12-18 2015-06-19 Univ Strasbourg Procede pour la determination des caracteristiques morphologiques d'un materiau solide cellulaire
WO2017000933A1 (de) * 2015-07-01 2017-01-05 Inoex Gmbh Verfahren und vorrichtung zur ermittlung einer schichteigenschaft einer schicht in einem extrusionsprozess
WO2017109075A1 (de) * 2015-12-22 2017-06-29 Fill Gesellschaft M.B.H. Verfahren zur herstellung eines geschäumten partikelschaummaterials

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2186991A (en) * 1986-02-20 1987-08-26 Dow Chemical Co Optical examination of a body surface
US5786000A (en) * 1996-08-28 1998-07-28 Berner; Rolf E. Continuous molding machine with pusher
DE102019127708A1 (de) * 2019-10-15 2021-04-15 Kurtz Gmbh Verfahren und Vorrichtung zum Sortieren und/oder Abmessen der Menge von Schaumstoffpartikeln
DE102019215878B4 (de) * 2019-10-15 2023-11-30 Adidas Ag Verfahren und Vorrichtung zum Sortieren und/oder Abmessen der Menge von Schaumstoffpartikeln
KR102587905B1 (ko) * 2023-01-18 2023-10-12 일진파워텍(주) 절단 및 가압 기반의 지중관로 보수 시스템

Citations (5)

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Publication number Priority date Publication date Assignee Title
US2891722A (en) * 1956-09-25 1959-06-23 Rank Cintel Ltd Apparatus for sizing objects
US3368007A (en) * 1964-09-17 1968-02-06 Industrial Nucleonics Corp Rotary die extruder system
US3646188A (en) * 1970-02-03 1972-02-29 Du Pont Process for improving uniformity of polymeric film
US3695765A (en) * 1969-04-25 1972-10-03 Laporte Industries Ltd Method for measuring and/or monitoring the size of particles in suspension
US3797937A (en) * 1972-03-01 1974-03-19 Environmental Systems Corp System for making particle measurements

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2891722A (en) * 1956-09-25 1959-06-23 Rank Cintel Ltd Apparatus for sizing objects
US3368007A (en) * 1964-09-17 1968-02-06 Industrial Nucleonics Corp Rotary die extruder system
US3695765A (en) * 1969-04-25 1972-10-03 Laporte Industries Ltd Method for measuring and/or monitoring the size of particles in suspension
US3646188A (en) * 1970-02-03 1972-02-29 Du Pont Process for improving uniformity of polymeric film
US3797937A (en) * 1972-03-01 1974-03-19 Environmental Systems Corp System for making particle measurements

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4374322A (en) * 1979-04-27 1983-02-15 W. C. Heraeus Gmbh Apparatus for controlling the absorption of one or more color components in a dyeing fluid
US4412961A (en) * 1981-12-23 1983-11-01 Mobil Oil Corporation Method and apparatus for measurement and control of cell size in a foam structure
US4699516A (en) * 1984-10-29 1987-10-13 The Dow Chemical Company Apparatus and methods for determining cell size
DE3813662A1 (de) * 1987-04-23 1988-11-17 Hajime Industries Oberflaechenpruefgeraet
US4868404A (en) * 1987-04-23 1989-09-19 Hajime Industries, Ltd. Surface inspection apparatus using a mask system to monitor uneven surfaces
US5248459A (en) * 1989-11-25 1993-09-28 Kanegafuchi Chemical Industry Co., Ltd. Method of manufacturing molded resin foam and apparatus therefor
US5509795A (en) * 1993-11-23 1996-04-23 Schuller International, Inc. Apparatus for continuously foaming a polyimide powder
US5912729A (en) * 1996-06-17 1999-06-15 Basf Corporation Measurement of plastic foam cell size using a visualization technique
FR3015021A1 (fr) * 2013-12-18 2015-06-19 Univ Strasbourg Procede pour la determination des caracteristiques morphologiques d'un materiau solide cellulaire
WO2015092264A1 (fr) * 2013-12-18 2015-06-25 Universite De Strasbourg Procede pour la determination des caracteristiques morphologiques d'un materiau solide cellulaire
WO2017000933A1 (de) * 2015-07-01 2017-01-05 Inoex Gmbh Verfahren und vorrichtung zur ermittlung einer schichteigenschaft einer schicht in einem extrusionsprozess
US11225008B2 (en) 2015-07-01 2022-01-18 Inoex Gmbh Method and device for determining a layer property of a layer in an extrusion process
WO2017109075A1 (de) * 2015-12-22 2017-06-29 Fill Gesellschaft M.B.H. Verfahren zur herstellung eines geschäumten partikelschaummaterials

Also Published As

Publication number Publication date
NL7511471A (nl) 1976-04-01
GB1522644A (en) 1978-08-23
ES441291A1 (es) 1977-04-01
DE2543292A1 (de) 1976-04-08
IT1042966B (it) 1980-01-30
BE833910A (fr) 1976-03-26
CA1065567A (en) 1979-11-06
FR2285983A1 (fr) 1976-04-23
JPS5161885A (cs) 1976-05-28
FR2285983B1 (cs) 1980-04-30

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